Fluoropolymer containing ethylenically unsaturated groups, and curable resin compositions and antireflection coatings, made by using the same

ABSTRACT

An ethylenically unsaturated group-containing fluoropolymer, which is obtained by reacting a compound containing one isocyanate group and at least one ethylenically unsaturated group, and a hydroxyl group-containing fluoropolymer at an isocyanate group/hydroxyl group molar ratio of 1.1 to 1.9. According to the present invention, an ethylenically unsaturated group-containing fluoropolymer having superior antiscratching property, coating property and durability, as well as a curable resin composition and an antireflection film using the same can be provided.

TECHNICAL FIELD

The present invention relates to an ethylenically unsaturatedgroup-containing fluoropolymer, as well as a curable resin compositionand an antireflection film using the same. More precisely, the presentinvention relates to an ethylenically unsaturated group-containingfluoropolymer, as well as a curable resin composition which contains theethylenically unsaturated group-containing fluoropolymer and can providea cured product exhibiting superior antiscratching property, coatingproperty and durability when it is cured, and an antireflection filmhaving a low refractive index layer comprising such a cured product.

BACKGROUND ART

To prevent reflection of outside lights and improve image quality ofvarious display panels such as liquid crystal display panels, coldcathode ray tube panels and plasma displays, being desired is anantireflection film having a low refractive index layer comprising acured product exhibiting a superior low refractive index property,antiscratching property, coating property and durability.

Surfaces of these display panels are often wiped with gauze impregnatedwith ethanol or the like to remove adhered fingerprints, dusts etc., andtherefore antiscratching property is desired.

In liquid crystal display panels, in particular, an antireflection filmis provided on a liquid crystal unit in a state that it is laminated ona polarizing plate. Further, for example, triacetyl cellulose etc. isused as a substrate. An antireflection film using such a substrateusually need to be saponified with an alkaline aqueous solution toincrease adhesion when it is adhered to the polarizing plate.

Accordingly, for use in liquid crystal display panels, an antireflectionfilm exhibiting superior durability, especially superior alkaliresistance, is desired.

As materials for a low refractive index layer of antireflection films,for example, fluorine resin type paints containing a hydroxylgroup-containing fluoropolymer are known, and they are disclosed inJP-A-57-34107, JP-A-59-189108, JP-A-60-67518 and so forth.

However, for such fluorine resin type paints, it is necessary to heatthe hydroxyl group-containing fluoropolymer and a curing agent such as amelamine resin in the presence of an acidic catalyst to crosslink themfor curing a coated film. Therefore, such fluorine resin type paintshave problems depending on the heating conditions that curing time isextremely extended or types of usable substrates are limited.

Furthermore, the obtained coated film also has problems of poorantiscratching property and durability, although it exhibits superiorweather resistance.

Therefore, to solve the above problems, JP-B-6-35559 proposes a paintcomposition containing an unsaturated group- and fluorine-containingvinyl polymer obtained by reacting an isocyanate group-containingunsaturated compound having at least one isocyanate group and at leastone addition-polymerizable unsaturated group and a hydroxylgroup-containing fluoropolymer at an isocyanate group/hydroxyl groupnumber ratio of 0.01 to 1.0.

However, in the aforementioned patent publication, the unsaturatedgroup- and fluorine-containing vinyl polymer is prepared without usingthe isocyanate group-containing unsaturated compound in an amountsufficient for reacting all of the hydroxyl groups in the hydroxylgroup-containing fluoropolymer so as to intentionally leave unreactedhydroxyl groups in the polymer.

Therefore, although a paint composition containing such a polymer can becured at a low temperature in a short period of time, a curing agentsuch as a melamine resin must be further used to react the remaininghydroxyl groups for curing. Further, the coated film obtained in theaforementioned patent publication has a problem that coating propertyand antiscratching property cannot be considered sufficient.

Accordingly, an object of the present invention is to provide anethylenically unsaturated group-containing fluoropolymer which exhibitssuperior antiscratching property, coating property and durability, acurable resin composition and an antireflection film using the same.

DISCLOSURE OF THE INVENTION

According to the present invention, there is provided an ethylenicallyunsaturated group-containing fluoropolymer obtained by reacting acompound containing one isocyanate group and at least one ethylenicallyunsaturated group and a hydroxyl group-containing fluoropolymer at anisocyanate group/hydroxyl group molar ratio of 1.1 to 1.9.

By reacting them at such a molar ratio, an ethylenically unsaturatedgroup-containing fluoropolymer in which all of hydroxyl groups arereacted with isocyanate groups can be obtained. As a result,antiscratching property such as gauze abrasion resistance and durabilitysuch as alkali resistance are improved.

Further, in the ethylenically unsaturated group-containing fluoropolymerof the present invention, the aforementioned hydroxyl group-containingfluoropolymer preferably contains 20 to 70% by mole of the followingstructural unit (a), 10 to 70% by mole of the following structural unit(b) and 5 to 70% by mole of the following structural unit (c) and has anumber average molecular weight of 5,000 to 500,000 in terms ofpolystyrene as measured by gel permeation chromatography.

-   (a) Structural unit represented by the following general formula (1)-   (b) Structural unit represented by the following general formula (2)-   (c) Structural unit represented by the following general formula (3)

With such a configuration, a coated film exhibiting superior lowrefractive index property, antiscratching property, coating property anddurability can be obtained.

In the general formula (1), R¹ represents a fluorine atom, fluoroalkylgroup or group represented as —OR² (R² represents an alkyl group orfluoroalkyl group).

In the general formula (2), R³ represents a hydrogen atom or methylgroup, R⁴ represents an alkyl group, group represented as —(CH₂)_(x)—OR⁵or —OCOR⁵ (R⁵ represents an alkyl group or glycidyl group, and xrepresents a number of 0 or 1), carboxyl group or alkoxycarbonyl group.

In the general formula (3), R⁶ represents a hydrogen atom or methylgroup, R⁷ represents a hydrogen atom or hydroxyalkyl group, and vrepresents a number of 0 or 1.

Further, in the ethylenically unsaturated group-containing fluoropolymerof the present invention, the aforementioned hydroxyl group-containingfluoropolymer preferably further contains 0.1 to 10% by mole of thefollowing structural unit (d) derived from an azo group-containingpolysiloxane compound.

-   (d) Structural unit represented by the following general formula (4)

In the general formula (4), R⁸ and R⁹ may be identical or different andrepresent a hydrogen atom, alkyl group, halogenated alkyl group or arylgroup.

If the structural unit (d) is contained, antiscratching property isimproved.

Further, the ethylenically unsaturated group-containing fluoropolymer ofthe present invention preferably contains the aforementioned structuralunit (d) as a part of the following structural unit (e).

-   (e) Structural unit represented by the following general formula (5)

In the general formula (5), R¹⁰ to R¹³ represent a hydrogen atom, alkylgroup or cyano group, R¹⁴ to R¹⁷ represent a hydrogen atom or alkylgroup, p and q represent a number of 1 to 6, s and t represent a numberof 0 to 6, and y represents a number of 1 to 200].

Further, in the ethylenically unsaturated group-containing fluoropolymerof the present invention, the aforementioned hydroxyl group-containingfluoropolymer preferably further contains 0.1 to 5% by mole of thefollowing structural unit (f).

-   (f) Structural unit represented by the following general formula (6)

In the general formula (6), R¹⁸ represents a group having emulsifyingaction.

If the structural unit (f) is contained, coating property is improved.

Further, in the ethylenically unsaturated group-containing fluoropolymerof the present invention, the ethylenically unsaturated group in theaforementioned compound containing one isocyanate group and at least oneethylenically unsaturated group is preferably (meth)acryloyl group.

If the ethylenically unsaturated group is (meth)acryloyl group, theethylenically unsaturated group-containing fluoropolymer can bepolymerized by a polymerization reaction caused by radicals generated byultraviolet ray irradiation or heating to cure a coated film.

Further, in the ethylenically unsaturated group-containing fluoropolymerof the present invention, the aforementioned compound containing oneisocyanate group and at least one ethylenically unsaturated group ispreferably 2-(meth)acryloyloxyethyl isocyanate.

If 2-(meth)acryloyloxyethyl isocyanate is used, an ethylenicallyunsaturated group can be introduced while maintaining a low refractiveindex.

Another embodiment of the present invention is a curable resincomposition containing the aforementioned ethylenically unsaturatedgroup-containing fluoropolymer, a polyfunctional (meth)acrylate compoundcontaining at least two (meth)acryloyl groups and/or afluorine-containing (meth)acrylate compound containing at least one(meth)acryloyl group.

With such a curable resin composition, a cured product which exhibitssuperior antiscratching property, coating property and durability can beobtained.

Further, the curable resin composition of the present inventionpreferably further contains a compound that generates active species byirradiation of an active energy ray or heating.

If such a compound that generates active species is contained, thecomposition can be appropriately cured.

Further, another embodiment of the present invention is anantireflection film containing a low refractive index layer comprising acured product obtained by curing the aforementioned curable resincomposition.

If such a low refractive index layer is contained, an antireflectionfilm which exhibits superior antiscratching property, coating propertyand durability can be obtained.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a cross sectional view of an antireflection film accordingto one embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereafter, embodiments of the ethylenically unsaturated group-containingfluoropolymer, curable resin composition and antireflection film of thepresent invention will be explained.

1. Ethylenically Unsaturated Group-containing Fluoropolymer

The ethylenically unsaturated group-containing fluoropolymer of thepresent invention can be obtained by reacting a compound containing oneisocyanate group and at least one ethylenically unsaturated group and ahydroxyl group-containing fluoropolymer at an isocyanate group/hydroxylgroup molar ratio of 1.1 to 1.9.

(1) Compound Containing One Isocyanate Group and at Least OneEthylenically Unsaturated Group

The compound containing one isocyanate group and at least oneethylenically unsaturated group is not particularly limited so long asit is a compound that contains one isocyanate group and at least oneethylenically unsaturated group in the molecule.

If two or more isocyanate groups are contained, gelation may occur atthe time of the reaction with the hydroxyl group-containingfluoropolymer.

Further, a compound having (meth)acryloyl group as the aforementionedethylenically unsaturated group is more preferred because such acompound makes it easier to cure the curable resin composition explainedlater.

Examples of such a compound include a single kind of compound orcombinations of two or more kinds of compounds selected from2-(meth)acryloyloxyethyl isocyanate, 2-(meth)acryloyloxypropylisocyanate.

Such compounds can also be synthesized by reacting a diisocyanate with ahydroxyl group-containing (meth)acrylate.

In this case, examples of the diisocyanate include a single kind ofcompound or combinations of two or more kinds of compounds selected from2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylenediisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate,m-phenylene diisocyanate, p-phenylene diisocyanate,3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethanediisocyanate, 3,3′-dimethylphenylene diisocyanate, 4,4′-biphenylenediisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate,methylene bis(4-cyclohexyl isocyanate), 2,2,4-trimethylhexamethylenediisocyanate, bis(2-isocyanatoethyl)fumarate, 6-isopropyl-1,3-phenyldiisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate,hydrogenated diphenylmethane diisocyanate,1,3-bis(isocyanatomethyl)cyclohexane, tetramethylxylylene diisocyanate,2,5(or 6)-bis(isocyanatomethyl)-bicyclo[2.2.1]heptane and so forth.

Among these, 2,4-tolylene diisocyanate, isophorone diisocyanate,xylylene diisocyanate, methylene bis(4-cyclohexyl isocyanate) and1,3-bis(isocyanatomethyl)cyclohexane are particularly preferred.

Examples of the hydroxyl group-containing (meth)acrylate include asingle kind of compound or combinations of two or more kinds ofcompounds selected from 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, caprolactone(meth)acrylate, polypropylene glycol (meth)acrylate, dipentaerythritolpenta(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritoldi(meth)acrylate monostearate, isocyanuric acid EO-modifieddi(meth)acrylate and so forth.

Among these, 2-hydroxyethyl (meth)acrylate and pentaerythritoltri(meth)acrylate are particularly preferred.

Examples of commercially available products of hydroxyl group-containingpolyfunctional (meth)acrylate include HEA (trade name, produced by OsakaOrganic Chemical Industry Ltd.), KAYARAD DPHA and PET-30 (trade names,produced by Nippon Kayaku Co., Ltd.), ARONIX M-215, M-233, M-305 andM-400 (trade names, produced by Toagosei Co., Ltd.) and so forth.

When the ethylenically unsaturated group-containing fluoropolymer issynthesized from a diisocyanate and a hydroxyl group-containingpolyfunctional (meth)acrylate, the amount of the hydroxylgroup-containing polyfunctional (meth)acrylate is preferably 1 to 1.2moles per 1 mole of the diisocyanate.

Examples of the method for synthesizing such a compound include a methodof charging whole amounts of the diisocyanate and the hydroxylgroup-containing (meth)acrylate to perform the reaction, a method ofadding the diisocyanate dropwise to the hydroxyl group-containing(meth)acrylate to perform the reaction and so forth.

(2) Hydroxyl Group-containing Fluoropolymer

{circle over (1)} Structural Unit (a)

In the aforementioned general formula (1), examples of the fluoroalkylgroup as R¹ and R² include fluoroalkyl groups containing 1 to 6 carbonatoms such as trifluoromethyl group, perfluoroethyl group,perfluoropropyl group, perfluorobutyl group, perfluorohexyl group andperfluorocyclohexyl group. Further, examples of the alkyl group as R²include alkyl groups containing 1 to 6 carbon atoms such as methylgroup, ethyl group, propyl group, butyl group, hexyl group andcyclohexyl group.

The structural unit (a) can be introduced by using a fluorine-containingvinyl monomer as a polymerization component. Such a fluorine-containingvinyl monomer is not particularly limited so long as it is a compoundhaving at least one polymerizable unsaturated double bond and at leastone fluorine atom. Examples thereof include a single kind of compound orcombinations of two or more kinds of compounds selected fromfluoroolefins such as tetrafluoroethylene, hexafluoropropylene and3,3,3-trifluoropropylene; alkyl perfluorovinyl ethers or alkoxyalkylperfluorovinyl ethers; perfluoro(alkyl vinyl ethers) such asperfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether),perfluoro(propyl vinyl ether), perfluoro(butyl vinyl ether) andperfluoro(isobutyl vinyl ether); and perfluoro(alkoxyalkyl vinyl ethers)such as perfluoro(propoxypropyl vinyl ether).

Among these, hexafluoropropylene and perfluoro(alkyl vinyl ether) orperfluoro(alkoxyalkyl vinyl ether) are more preferred, and combinationsof these are still more preferred.

The content of the structural unit (a) is 20 to 70% by mole based on thetotal amount of the hydroxyl group-containing fluoropolymer which istaken as 100% by mole. This is because if the content is lower than 20%by mole, it may become difficult to obtain a low refractive indexproperty, which is an optical characteristic of a fluorine-containingmaterial intended by the present invention, whereas if the contentexceeds 70% by mole, solubility in an organic solvent, transparency oradhesion to a substrate of the hydroxyl group-containing fluoropolymermay be degraded.

Further, for the aforementioned reasons, the content of the structuralunit (a) is preferably 25 to 65% by mole, more preferably 30 to 60% bymole, based on the total amount of the hydroxyl group-containingfluoropolymer.

{circle over (2)} Structural Unit (b)

In the general formula (2), examples of the alkyl group as R⁴ or R⁵include alkyl groups containing 1 to 12 carbon atoms such as methylgroup, ethyl group, propyl group, hexyl group, cyclohexyl group andlauryl group, and examples of the alkoxycarbonyl group includemethoxycarbonyl group, ethoxycarbonyl group and so forth.

The structural unit (b) can be introduced by using a vinyl monomerhaving the aforementioned substituents as a polymerization component.Examples of such a vinyl monomer include a single kind of compound orcombinations of two or more kinds of compounds selected from alkyl vinylethers or cycloalkyl vinyl ethers such as methyl vinyl ether, ethylvinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinylether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinylether, n-hexyl vinyl ether, n-octyl vinyl ether, n-dodecyl vinyl ether,2-ethylhexyl vinyl ether and cyclohexyl vinyl ether; allyl ethers suchas ethyl allyl ether and butyl allyl ether; carboxylic acid vinyl esterssuch as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate,vinyl caproate, vinyl versate and vinyl stearate; (meth)acrylic acidesters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl(meth)acrylate, isobutyl (meth)acrylate, 2-methoxyethyl (meth)acrylate,2-ethoxyethyl (meth)acrylate and 2-(n-propoxy)ethyl (meth)acrylate;unsaturated carboxylic acids such as (meth)acrylic acid, crotonic acid,maleic acid, fumaric acid and itaconic acid and so forth.

The content of the structural unit (b) is 10 to 70% by mole based on thetotal amount of the hydroxyl group-containing fluoropolymer which istaken as 100% by mole. This is because if the content is lower than 10%by mole, solubility of the hydroxyl group-containing fluoropolymer in anorganic solvent may be degraded, whereas if the content exceeds 70% bymole, optical characteristics such as transparency and low reflectanceproperty of the hydroxyl group-containing fluoropolymer may be degraded.

Further, for the aforementioned reasons, the content of the structuralunit (b) is preferably 20 to 60% by mole, more preferably 30 to 60% bymole, based on the total amount of the hydroxyl group-containingfluoropolymer.

{circle over (3)} Structural Unit (c)

In the general formula (3), examples of the hydroxyalkyl group as R⁷include 2-hydroxyethyl group, 2-hydroxypropyl group, 3-hydroxypropylgroup, 4-hydroxybutyl group, 3-hydroxybutyl group, 5-hydroxypentyl groupand 6-hydroxyhexyl group.

The structural unit (c) can be introduced by using a hydroxylgroup-containing vinyl monomer as a polymerization component. Examplesof such a hydroxyl group-containing vinyl monomer include hydroxylgroup-containing vinyl ethers such as 2-hydroxyethyl vinyl ether,3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutylvinyl ether, 3-hydroxybutyl vinyl ether, 5-hydroxypentyl vinyl ether and6-hydroxyhexyl vinyl ether, hydroxyl group-containing allyl ethers suchas 2-hydroxyethyl allyl ether, 4-hydroxybutyl allyl ether and glycerolmonoallyl ether, allyl alcohol and so forth.

Further, as the hydroxyl group-containing vinyl monomer, in addition tothose mentioned above, 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, caprolactone(meth)acrylate, polypropylene glycol (meth)acrylate and so forth can beused.

The content of the structural unit (c) is preferably 5 to 70% by molebased on the total amount of the hydroxyl group-containing fluoropolymerwhich is taken as 100% by mole. This is because if the content is lowerthan 5% by mole, solubility of the hydroxyl group-containingfluoropolymer in an organic solvent may be degraded, whereas if thecontent exceeds 70% by mole, optical characteristics of the hydroxylgroup-containing fluoropolymer such as transparency or low reflectanceproperty may be degraded.

Further, for the aforementioned reasons, the content of the structuralunit (c) is more preferably 5 to 40% by mole, still more preferably 5 to30% by mole, based on the total amount of the hydroxyl group-containingfluoropolymer.

{circle over (4)} Structural Unit (d) and Structural Unit (e)

Further, it is also preferred that the hydroxyl group-containingfluoropolymer further contains the aforementioned structural unit (d).Hereafter, the structural unit (d) will be explained.

In the general formula (4), examples of the alkyl group as R⁸ or R⁹include alkyl groups containing 1 to 3 carbon atoms such as methylgroup, ethyl group and propyl group, examples of the halogenated alkylgroup include fluoroalkyl groups containing 1 to 4 carbon atoms such astrifluoromethyl group, perfluoroethyl group, perfluoropropyl group andperfluorobutyl group, and examples of the aryl group include phenylgroup, benzyl group and naphthyl group.

The structural unit (d) can be introduced by using an azogroup-containing polysiloxane compound having a polysiloxane segmentrepresented by the general formula (4). Examples of such an azogroup-containing polysiloxane compound include compounds represented bythe following general formula (7).

In the general formula (7), R¹⁰ to R¹³, R¹⁴ to R¹⁷, p, q, s, t and yhave the same meanings as defined in the aforementioned general formula(5), and z represents a number of 1 to 20.

If a compound represented by the general formula (7) is used, thestructural unit (d) shall be contained in the hydroxyl group-containingfluoropolymer as a part of the structural unit (e). In this case, in thegeneral formula (5), examples of the alkyl groups as R¹⁰ to R¹³ includealkyl groups containing 1 to 12 carbon atoms such as methyl group, ethylgroup, propyl group, hexyl group and cyclohexyl group, and examples ofthe alkyl groups as R¹⁴ to R¹⁷ include alkyl groups containing 1 to 3carbon atoms such as methyl group, ethyl group and propyl group.

In the present invention, the azo group-containing polysiloxane compoundrepresented by the aforementioned general formula (7) is particularlypreferably a compound represented by the following general formula (8).

In the general formula (8), y and z have the same meanings as defined inthe general formula (7).

The content of the structural unit (d) is preferably 0.1 to 10% by molebased on the total amount of the hydroxyl group-containing fluoropolymerwhich is taken as 100% by mole. This is because if the content is lowerthan 0.1% by mole, surface lubricity of a cured coated film may bedegraded, which may result in degradation of the antiscratching propertyof the coated film, whereas if the content exceeds 10% by mole,transparency of the hydroxyl group-containing fluoropolymer may bedegraded, and repellency or the like may become likely to occur uponapplication when it is used as a coating material.

Further, for the aforementioned reasons, the content of the structuralunit (d) is more preferably 0.1 to 5% by mole, still more preferably 0.1to 3% by mole, based on the total amount of the hydroxylgroup-containing fluoropolymer. For the same reasons, the content of thestructural unit (e) is preferably determined so that the content of thestructural unit (d) contained therein should be within theaforementioned range.

{circle over (5)} Structural Unit (f)

Further, it is also preferred that the hydroxyl group-containingfluoropolymer further contains the aforementioned structural unit (f).Hereafter, the structural unit (f) will be explained.

In the general formula (6), the group having emulsifying action as R¹⁸is preferably a group which has both of a hydrophobic group and ahydrophilic group, and in which the hydrophilic group has a structure ofpolyether such as polyethylene oxide and polypropylene oxide.

Examples of such a group having emulsifying action include groupsrepresented by the following general formula (9).

In the general formula (9), n represents a number of 1 to 20, mrepresents a number of 0 to 4, and u represents a number of 3 to 50.

The structural unit (f) can be introduced by using a reactive emulsifieras a polymerization component. Examples of such a reactive emulsifierinclude compounds represented by the following general formula (10).

In the general formula (10), n, m and u have the same meanings asdefined in the aforementioned general formula (9).

The content of the structural unit (f) is preferably 0.1 to 5% by molebased on the total amount of the hydroxyl group-containing fluoropolymerwhich is taken as 100% by mole. This is because if the content is 0.1%by mole or higher, solubility of the hydroxyl group-containingfluoropolymer in a solvent is improved, and if the content is 5% by moleof or lower, adhesion of the curable resin composition does not undulyincrease, which results in easy handling, and moisture resistance is notdegraded even in use as a coating material or the like.

Further, for the aforementioned reasons, the content of the structuralunit (f) is more preferably 0.1 to 3% by mole, still more preferably 0.2to 3% by mole, based on the total amount of the hydroxylgroup-containing fluoropolymer.

{circle over (6)} Molecular Weight

The number average molecular weight of the hydroxyl group-containingfluoropolymer in terms of polystyrene is preferably 5000 to 500,000 asmeasured by gel permeation chromatography (hereinafter referred to as“GPC”) using tetrahydrofuran (hereinafter referred to as “THF”) as asolvent. This is because if the number average molecular weight is lessthan 5000, mechanical strength of the hydroxyl group-containingfluoropolymer may be degraded, whereas if the number average molecularweight exceeds 500,000, viscosity of the curable resin compositionexplained later may increase, and thus it may become difficult to coat athin film.

Further, for the aforementioned reasons, the number average molecularweight of the hydroxyl group-containing fluoropolymer in terms ofpolystyrene is more preferably 10,000 to 300,000, still more preferably10,000 to 100,000.

(3) Molar Ratio for Reaction

The ethylenically unsaturated group-containing fluoropolymer of thepresent invention is obtained by reacting the aforementioned compoundcontaining one isocyanate group and at least one ethylenicallyunsaturated group with the hydroxyl group-containing fluoropolymer at anisocyanate group/hydroxyl group molar ratio of 1.1 to 1.9. This isbecause if the molar ratio is lower than 1.1, antiscratching propertyand durability may be degraded, whereas if the molar ratio exceeds 1.9,antiscratching property of a coated film of a curable resin compositionmay be degraded after immersion in an alkaline aqueous solution.

Further, for the aforementioned reasons, the isocyanate group/hydroxylgroup molar ratio is preferably 1.1 to 1.5, more preferably 1.2 to 1.5.

2. Curable Resin Composition

The curable resin composition of the present invention contains thefollowing components (a) to (c). Among these components, the component(a) is an essential component, and the component (b) and the component(c) are preferably contained.

-   (a) Ethylenically unsaturated group-containing fluoropolymer    mentioned above-   (b) Polyfunctional (meth)acrylate compound containing at least two    (meth)acryloyl groups and/or a fluorine-containing (meth)acrylate    compound containing at least one (meth)acryloyl group-   (c) Compound generating an active species by irradiation of an    active energy ray or heating

The addition amount of the component (a) is not particularly limited,and it is usually 3 to 95% by weight. This is because if the additionamount is less than 3% by weight, refractive index of a cured coatedfilm of the curable resin composition may increase, and thus sufficientantireflection effect may not be obtained, whereas if the additionamount exceeds 95% by weight, antiscratching property of a cured coatedfilm of the curable resin composition may not be obtained.

Further, for the aforementioned reasons, the addition amount of thecomponent (a) is more preferably 5 to 90% by weight, still morepreferably 10 to 80% by weight.

The addition amount of the component (b) is not particularly limited,and it is usually 3 to 95% by weight. This is because if the additionamount is less than 3% by weight, antiscratching property of a curedcoated film of the curable resin composition may not be obtained,whereas if the addition amount exceeds 95% by weight, refractive indexof a cured coated film of the curable resin composition may increase,and thus sufficient antireflection effect may not be obtained.

Further, for the aforementioned reasons, the addition amount of thecomponent (b) is more preferably 5 to 90% by weight, still morepreferably 10 to 80% by weight.

(1) Polyfunctional (meth)acrylate Compound Containing at Least Two(meth)acryloyl Groups

The polyfunctional (meth)acrylate compound containing at least two(meth)acryloyl groups is used to improve antiscratching property of acured product obtained by curing the curable resin composition and anantireflection film using the same.

This compound is not particularly limited so long as it is a compoundcontaining at least two (meth)acryloyl groups in the molecule. Examplesthereof include a single kind of compound or combinations of two or morekinds of compounds selected from neopentyl glycol di(meth)acrylate,trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate,trimethylolethane tri(meth)acrylate, pentaerythritoltetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate,alkyl-modified dipentaerythritol tetra(meth)acrylate, dipentaerythritolpenta(meth)acrylate, alkyl-modified dipentaerythritolpenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate,caprolactone-modified dipentaerythritol hexa(meth)acrylate,ditrimethylolpropane tetra(meth)acrylate, “U-15HA” (trade name, producedby Shin Nakamura Kagaku Co., Ltd.) and so forth.

Among these, neopentyl glycol di(meth)acrylate, dipentaerythritolhexa(meth)acrylate, pentaerythritol tetra(meth)acrylate,dipentaerythritol penta(meth)acrylate and caprolactone-modifieddipentaerythritol hexa(meth)acrylate are particularly preferred.

(2) Fluorine-containing (meth)acrylate Compound Containing at Least One(meth)acryloyl Group

The fluorine-containing (meth)acrylate compound containing at least one(meth)acryloyl group is used to decrease refractive index of the curableresin composition.

This compound is not particularly limited so long as it is afluorine-containing (meth)acrylate compound containing at least one(meth)acryloyl group. Examples thereof include a single kind of compoundor combinations of two or more kinds of compounds selected fromperfluorooctylethyl (meth)acrylate, octafluoropentyl (meth)acrylate,trifluoroethyl (meth)acrylate and so forth.

(3) Compound Generating Active Species by Irradiation of Active EnergyRay or Heating

The compound generating active species by irradiation of active energyray or heating is used to cure the curable resin composition.

(i) Compound Generating Active Species by Irradiation of Active EnergyRay

Examples of the compound generating active species by irradiation ofactive energy ray (hereinafter referred to as “photopolymerizationinitiator”) include photoradical generators generating a radical as anactive species and so forth.

The active energy ray is defined as an energy ray which can generate anactive species by decomposing a compound generating an active species.Examples of such an active energy ray include light energy rays such asvisible lights, ultraviolet rays, infrared rays, X-rays, α-rays, β-raysand γ-rays. However, an ultraviolet ray is preferably used in view ofhaving a certain energy level and exhibiting high curing speed as wellas requiring a relatively inexpensive and small-size irradiationapparatus.

{circle over (1)} Type

Examples of the photoradical generator include acetophenone,acetophenone benzyl ketal, anthraquinone,1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, carbazole,xanthone, 4-chlorobenzophenone, 4,4′-diaminobenzophenone,1,1-dimethoxydeoxybenzoin, 3,3′-dimethyl-4-methoxybenzophenone,thioxanthone, 2,2-dimethoxy-2-phenylacetophenone,1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one,2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one,triphenylamine, 2,4,6-trimethylbenzoyldiphenylphosphine oxide,1-hydroxycyclohexyl phenyl ketone,2-hydroxy-2-methyl-1-phenylpropan-1-one, fluorenone, fluorene,benzaldehyde, benzoin ethyl ether, benzoin propyl ether, benzophenone,Michler's ketone, 3-methylacetophenone,3,3′,4,4′-tetra(tert-butylperoxycarbonyl)benzophenone (BTTB),2-(dimethylamino)-1-[4-(morphonyl)phenyl]-2-phenylmethyl)-1-buthanone,4-benzoyl-4′-methyldiphenyl sulfide, benzil, combinations of BTTB withxanthene, thioxanthene, cumarin, ketocumarin or other pigmentsensitizers and so forth.

Among these photopolymerization initiators,2,2-dimethoxy-2-phenylacetophenone,2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenylketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide,2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one,2-(dimethylamino)-1-[4-(morphonyl)phenyl]-2-phenylmethyl)-1-buthanoneand so forth are preferred, and 1-hydroxycyclohexyl phenyl ketone,2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one,2-(dimethylamino)-1-[4-(morphonyl)phenyl]-2-phenylmethyl)-1-buthanoneand so forth are more preferred.

{circle over (2)} Addition Amount

Although the addition amount of the photopolymerization initiator is notparticularly limited, it is preferably 0.01 to 20 parts by weight withregard to 100 parts by weight of the ethylenically unsaturatedgroup-containing fluoropolymer. This is because if the addition amountis less than 0.01 parts by weight, the curing reaction may becomeinsufficient, and thus antiscratching property and antiscratchingproperty after immersion in an alkaline aqueous solution may bedegraded, whereas if the addition amount of the photopolymerizationinitiator exceeds 20 parts by weight, refractive index of a curedproduct may increase, and thus antireflection effect may be degraded.

Further, for the aforementioned reasons, the addition amount of thephotopolymerization initiator is more preferably 0.05 to 15 parts byweight, still more preferably 0.1 to 15 parts by weight, with regard to100 parts by weight of the ethylenically unsaturated group-containingfluoropolymer.

(ii) Compound Generating Active Species by Heating

Examples of the compound generating active species by heating(hereinafter referred to as “thermal polymerization initiator”) includethermal radical generators generating a radical as an active species andso forth.

{circle over (1)} Type

Examples of the thermal radical generator include a single kind ofcompound or combinations of two or more kinds of compounds selected frombenzoyl peroxide, tert-butyl-oxybenzoate, azobisisobutyronitrile, acetylperoxide, lauryl peroxide, tert-butyl peracetate, cumyl peroxide,tert-butyl peroxide, tert-butyl hydroperoxide,2,2′-azobis(2,4-dimethylvaleronitrile),2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) and so forth.

{circle over (2)} Addition Amount

Although the addition amount of the thermal polymerization initiator isnot particularly limited either, it is preferably 0.01 to 20 parts byweight with regard to 100 parts by weight of the ethylenicallyunsaturated group-containing fluoropolymer. This is because if theaddition amount is less than 0.01 parts by weight, the curing reactionmay become insufficient, and thus antiscratching property andantiscratching property after immersion in an alkaline aqueous solutionmay be degraded, whereas if the addition amount of thephotopolymerization initiator exceeds 20 parts by weight, refractiveindex of a cured product may increase, and thus antireflection effectmay be degraded.

Further, for the aforementioned reasons, the addition amount of thethermal polymerization initiator is more preferably 0.05 to 15 parts byweight, still more preferably 0.1 to 15 parts by weight, with regard to100 parts by weight of the ethylenically unsaturated group-containingfluoropolymer.

(4) Organic Solvent

Further, an organic solvent is preferably added to the curable resincomposition. By adding an organic solvent as described above, anantireflection film can be uniformly formed as a thin film. Examples ofsuch an organic solvent include a single kind of solvent or combinationsof two or more kinds of solvents selected from methyl isobutyl ketone(hereinafter also referred to as “MIBK”), methyl ethyl ketone, methanol,ethanol, t-butanol, isopropanol and so forth.

Although the addition amount of the organic solvent is not particularlylimited either, it is preferably 100 to 100,000 parts by weight withregard to 100 parts by weight of the ethylenically unsaturatedgroup-containing fluoropolymer. This is because if the addition amountis less than 100 parts by weight, it may become difficult to adjustviscosity of the curable resin composition, whereas if the additionamount exceeds 100,000 parts by weight, storage stability of the curableresin composition may be degraded, or viscosity may be unduly decreasedso that handling may become difficult.

(5) Additives

So long as the object or effect of the present invention is notadversely affected, it is also preferred that the curable resincomposition further contains additives such as radicalphotopolymerization initiators, photosensitizers, polymerizationinhibitors, polymerization initiation aids, leveling agents, wettabilityimprovers, surfactants, plasticizers, ultraviolet absorbers,antioxidants, antistatic agents, silane coupling agents, inorganicfillers, pigments and dyes.

(6) Preparation Method

The curable resin composition of the present invention can be preparedby adding the aforementioned ethylenically unsaturated group-containingfluoropolymer, the aforementioned component (a) and/or component (b), aswell as the aforementioned component (c), organic solvent and additivesas required and mixing them at room temperature or under a heatingcondition. Specifically, it can be prepared by using a blender such as amixer, kneader, ball mill and three roll mill. When the mixing isperformed under a heating condition, it is preferably performed at atemperature below the decomposition starting temperature of the thermalpolymerization initiator.

(7) Curing Condition

The curing condition of the curable resin composition is notparticularly limited either. However, when an active energy ray is used,for example, exposure is preferably 0.01 to 10 J/cm².

This is because if the exposure is less than 0.01 J/cm², curing defectsmay occur, whereas if the exposure exceeds 10 J/cm², the curing time maybe unduly extended.

Further, for the aforementioned reasons, the exposure is more preferably0.1 to 5 J/cm², still more preferably 0.3 to 3 J/cm².

Further, when the curable resin composition is cured by heating, it ispreferably heated at a temperature in the range of 30 to 200° C. for 1to 180 minutes. By heating the composition which such conditions, anantireflection film having superior antiscratching property can be moreefficiently obtained without damaging a substrate and so forth.

Further, for the aforementioned reasons, the composition is morepreferably heated at a temperature in the range of 50 to 180° C. for 2to 120 minutes, still more preferably at a temperature in the range of80 to 150° C. for 5 to 60 minutes.

3. Antireflection Film

Hereafter, the antireflection film of the present invention will beexplained.

The antireflection film of the present invention contains a lowrefractive index layer comprising a cured product obtained by curing theaforementioned curable resin composition. Further, the antireflectionfilm of the present invention can contain a high refractive index layer,a hard coat layer and a substrate under the low refractive index layer.

FIG. 1 shows such an antireflection film 10. As shown in FIG. 1, a hardcoat layer 14, a high refractive index layer 16 and a low refractiveindex layer 18 are laminated on a substrate 12.

In the antireflection film, the high refractive index layer 16 may beformed directly on the substrate 12 without providing the hard coatlayer 14.

Further, a medium intermediate refractive index layer (not shown) may befurther provided between the high refractive index layer 16 and the lowrefractive index layer 18 or between the high refractive index layer 16and the hard coat layer 14.

(1) Low Refractive Index Layer

The low refractive index layer is formed with a cured product obtainedby curing the curable resin composition of the present invention. Sincethe configuration of the curable resin composition and the like are asdescribed above, detailed explanations thereof are omitted in thissection, and refractive index and thickness of the low refractive indexlayer will be explained hereafter.

(i) Refractive Index

Refractive index of a cured product obtained by curing the curable resincomposition (refractive index for Na-D line, measurement temperature:25° C.), that is, refractive index of the low refractive index film, ispreferably 1.45 or lower. This is because if the refractive index of thelow refractive index film exceeds 1.45, antireflection effect may bemarkedly degraded when it is used in combination with the highrefractive index film.

Therefore, the refractive index of the low refractive index film is morepreferably 1.44 or lower, still more preferably 1.43 or lower.

When two or more layers of the low refractive index film are provided,it is sufficient that at least one of these layers should have arefractive index value in the aforementioned range. That is, the otherlow refractive index film or films may have a value exceeding 1.45.

Further, when the low refractive index layer is provided, the refractiveindex thereof preferably differ from that of the high refractive indexlayer by 0.05 or more to provide more superior antireflection effect.This is because if the difference in the refractive index between thelow refractive index layer and the high refractive index layer is lessthan 0.05, synergic effect of these antireflection film layers may notbe obtained, and the antireflection effect may be degraded on thecontrary.

Thus, the difference in the refractive index between the low refractiveindex layer and the high refractive index layer is more preferably 0.1to 0.5, still more preferably 0.15 to 0.5.

(ii) Thickness

Further, although the thickness of the low refractive index layer is notparticularly limited either, it is preferably, for example, 50 to 300nm. This is because if the thickness of the low refractive index layeris less than 50 nm, adhesion to the high refractive index film as anundercoat may be degraded, whereas if the thickness exceeds 300 nm,optical interference may occur, which may result in degradation ofantireflection effect.

Therefore, the thickness of the low refractive index layer is morepreferably 50 to 250 nm, still more preferably 60 to 200 nm.

When a multilayer structure is formed with two or more low refractiveindex layers to obtain even better antireflection property, the totalthickness may be 50 to 300 nm.

(2) High Refractive Index Layer

The curable composition for forming the high refractive index layer isnot particularly limited, and preferred examples of film formingcomponent include a single kind of component or combinations of two ormore kinds of components selected from epoxy resins, phenolic resins,melamine resins, alkyd resins, cyanate resins, acrylic resins, polyesterresins, urethane resins, siloxane resins and so forth. By using any ofthese resins, a strong thin film can be formed as the high refractiveindex layer, and as a result, antiscratching property of theantireflection film can be markedly improved.

However, the refractive index of these resins themselves is usually 1.45to 1.62 and may be insufficient for obtaining high antireflectionperformance. Therefore, it is more preferable to add inorganic particleshaving a high refractive index, for example, metal oxide particles.Further, as for curing mechanism, although a curable composition thatcan be cured by heating, ultraviolet ray irradiation or electron beamirradiation can be used, it is more preferable to use an ultraviolet rayirradiation curable composition, which provides favorable productivity.

Although the thickness of the high refractive index layer is notparticularly limited, it is preferably, for example, 50 to 30,000 nm.This is because if the thickness of the high refractive index layer isless than 50 nm, antireflection effect or adhesion to a substrate may bedegraded when used in combination with the low refractive index layer,whereas if the thickness exceeds 30,000 nm, optical interference mayoccur, which may result in degradation of the antireflection effect onthe contrary.

Therefore, the thickness of the high refractive index layer is morepreferably 50 to 1,000 nm, still more preferably 60 to 500 nm.

Further, when a multilayer structure is formed with two or more of highrefractive index layers to obtain even better antireflection property,the total thickness may be 50 to 30,000 nm.

When a hard coat layer is formed between the high refractive index layerand the substrate, the thickness of the high refractive index layer maybe 50 to 300 nm.

(3) Hard Coat Layer

The material constituting the hard coat layer used for theantireflection film of the present invention is not particularlylimited. Examples of the material include a single kind of material orcombinations of two or more kinds of materials selected from siloxaneresins, acrylic resins, melamine resins, epoxy resins and so forth.

Further, although the thickness of the hard coat layer is notparticularly limited either, it is preferably 1 to 50 μm, morepreferably 5 to 10 μm. This is because if the thickness of the hard coatlayer is less than 1 μm, adhesion of the antireflection film to asubstrate may not be improved, whereas if the thickness exceeds 50 μm,it may be difficult to uniformly form the hard coat layer.

(5) Substrate

Type of the substrate used for the antireflection film of the presentinvention is not particularly limited. Examples include substrates madeof glass, polycarbonate resins, polyester resins, acrylic resins,triacetyl cellulose (TAC) resins and so forth. If the antireflectionfilm contains any of these substrates, superior antireflection effectcan be obtained in a wide range of fields in which antireflection filmsare used, such as a lens portion of camera, screen display portion oftelevision (CRT) and color filter in a liquid crystal display device.

EXAMPLES

The present invention will be explained more specifically with referenceto the following examples. However, the scope of the present inventionis not limited to the descriptions of these examples.

Production Example 1 Synthesis of Hydroxyl Group-containingFluoropolymer 1

Atmosphere in a stainless autoclave having an internal volume of 2.0 Land equipped with an electromagnetic stirrer was thoroughly replacedwith nitrogen gas. Then, to the autoclave, 400 g of ethyl acetate, 53.2g of perfluoro(propyl vinyl ether) (FPVE), 36.1 g of ethyl vinyl ether(EVE), 44.0 g of hydroxyethyl vinyl ether (HEVE), 1.00 g of lauroylperoxide, 6.0 g of azo group-containing polydimethylsiloxane representedby the aforementioned general formula (8) (trade name: VPS1001, producedby Wako Pure Chemical Industries) and 20.0 g of a nonionic reactiveemulsifier (trade name: NE-30, produced by Asahi Denka Co., Ltd.) werecharged, and after the mixture was cooled with dry ice/methanol to −50°C., oxygen in the system was purged with nitrogen gas again.

Then, 120.0 g of hexafluoropropylene (HFP) was charged, and thetemperature rise was started. The pressure in the autoclave was 5.3×10⁵Pa when the temperature in the autoclave reached 60° C. Then, thereaction was continued with stirring at 70° C. for 20 hours, and whenthe pressure decreased to 1.7×10⁵ Pa, the autoclave was cooled withwater to terminate the reaction.

After the temperature of the mixture reached room temperature, theunreacted monomers were discharged, and the autoclave was opened toobtain a polymer solution having a solid concentration of 26.4%. Theresulting polymer solution was poured into methanol to precipitate thepolymer, and the polymer was washed with methanol and dried at 50° C.under vacuum to obtain 220 g of hydroxyl group-containing fluoropolymer.This was designated a hydroxyl group-containing fluoropolymer 1. Theused monomers and solvents are shown in Table 1.

Number average molecular weight in terms of polystyrene and fluorinecontent of the obtained hydroxyl group-containing fluoropolymer 1 weremeasured by GPC and the alizarin complexone method, respectively.Further, proportions of monomer components constituting the hydroxylgroup-containing fluoropolymer 1 were determined from the results of¹H-NMR and ¹³C-NMR, elementary analysis and the fluorine content. Theresults are shown in Table 2.

VPS1001 is an azo group-containing polydimethylsiloxane represented bythe aforementioned general formula (8) and having a number averagemolecular weight of 70,000 to 90,000 and a molecular weight of thepolysiloxane moiety of about 10,000. NE-30 is a nonionic reactiveemulsifier represented by the aforementioned general formula (10),wherein n is 9, m is 1, and u is 30.

Further, relationships between the monomers shown in Table 2 and thestructural units are as follows. Monomer Structural unitHexafluoropropylene (a) Perfluoro(propyl vinyl ether) (a) Ethyl vinylether (b) Hydroxyethyl vinyl ether (c) NE-30 (f) Polydimethylsiloxanebase (d) structure

TABLE 1 Hydroxyl group- Hydroxyl group- Hydroxyl group- Hydroxyl group-Hydroxyl group- containing containing containing containing containingMonomer and solvent fluoropolymer 1 fluoropolymer 2 fluoropolymer 3fluoropolymer 4 fluoropolymer 5 Charged Hexafluoropropylene 120.0 120.0100.0 100.0 100.0 amount Perfluoro (propyl 53.2 53.2 76.3 76.3 76.3 (g)vinyl ether) Ethyl vinyl ether 36.1 64.9 48.2 48.2 48.2 Hydroxyethylvinyl 44.0 8.8 25.2 25.2 25.2 ether Lauroyl peroxide 1.0 1.0 1.0 1.0 1.0VPS1001 6.0 6.0 6.0 0.0 6.0 NE-30 20.0 20.0 20.0 20.0 0.0 Ethyl acetate400.0 400.0 400.0 400.0 400.0

TABLE 2 Hydroxyl group- Hydroxyl group- Hydroxyl group- Hydroxyl group-Hydroxyl group- containing containing containing containing containingMonomer fluoropolymer 1 fluoropolymer 2 fluoropolymer 3 fluoropolymer 4fluoropolymer 5 Monomer Hexafluoropropylene 41.1 41.1 33.8 34.8 33.9composition Perfluoro (propyl 10.0 10.0 14.2 14.9 14.4 (mole %) vinylether) Ethyl vinyl ether 20.9 40.6 33.2 34.9 33.5 Hydroxyethyl vinyl24.8 5.1 14.4 14.6 14.5 ether NE-30 0.8 0.8 0.8 0.8 0.0Polydimethylsiloxane base 2.4 2.4 3.6 0.0 3.7 structure (mole %) Numberaverage molecular weight 34,000 35,000 32,000 31,000 34,000

Production Example 2 Synthesis of Hydroxyl Group-containingFluoropolymer 2

A hydroxyl group-containing fluoropolymer was synthesized in the samemanner as in Production Example 1 except that the amounts of ethyl vinylether and hydroxyethyl vinyl ether used were changed as shown inTable 1. This was designated a hydroxyl group-containing fluoropolymer2. Proportions of the monomer components are shown in Table 2.

Production Example 3 Synthesis of Hydroxyl Group-containingFluoropolymer 3

A hydroxyl group-containing fluoropolymer was synthesized in the samemanner as in Production Example 1 except that the amounts ofhexafluoropropylene, perfluoro(propyl vinyl ether), ethyl vinyl etherand hydroxyethyl vinyl ether used were changed as shown in Table 1. Thiswas designated a hydroxyl group-containing fluoropolymer 3. Proportionsof the monomer components are shown in Table 2.

Production Example 4 Synthesis of Hydroxyl Group-containingFluoropolymer 4

A hydroxyl group-containing fluoropolymer was synthesized in the samemanner as in Production Example 3 except that VPS1001 was not used. Thiswas designated a hydroxyl group-containing fluoropolymer 4. Proportionsof the monomer components are shown in Table 2.

Production Example 5 Synthesis of Hydroxyl Group-containingfluoropolymer 5

A hydroxyl group-containing fluoropolymer was synthesized in the samemanner as in Production Example 3 except that NE-30 was not used. Thiswas designated a hydroxyl group-containing fluoropolymer 5. Proportionsof the monomer components are shown in Table 2.

Production Example 6 Preparation of Zirconia-containing Composition forHard Coat Layer

In dry air, to a solution comprising 7.8 parts ofmercaptopropyltrimethoxysilane and 0.2 part of dibutyltin dilaurate,20.6 parts of isophorone diisocyanate was added dropwise with stirringat 50° C. for one hour, and then the mixture was stirred at 60° C. for 3hours. To the reaction mixture, 71.4 parts of pentaerythritoltriacrylate was added dropwise at 30° C. for one hour, and then themixture was stirred with heating at 60° C. for 3 hours to obtain anorganic compound (S1).

Then, a mixture of 8.2 parts of the synthesized organic compound (S1),91.8 parts of toluene zirconia sol (number average particle diameter:0.01 μm, zirconia concentration: 30%), 41.2 parts of methyl ethyl ketoneand 0.1 part of ion exchanged water was stirred at 60° C. for 4 hours,then 1.3 parts of orthoformic acid methyl ester was added to themixture, and the mixture was further stirred with heating at the sametemperature for one hour to obtain a crosslinkable particle dispersion(dispersion a). In an amount of 2 g of this dispersion was weighed on analuminum plate, dried on a hot plate at 120° C. for one hour and weighedto determine the solid content. As a result, it was found to be 25%.

In a vessel shielded from ultraviolet rays, 312 parts of the produceddispersion a, 12.0 parts of dipentaerythritol hexaacrylate, 9.0 parts ofpentaerythritol triacrylate and 1.0 part of2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one were stirredat 50° C. for 2 hours under dry air flow to obtain a composition forhard coat layer as a uniform solution. In an amount of 2 g of thiscomposition was weighed on an aluminum plate, dried on a hot plate at120° C. for one hour and weighed to determine the solid content. As aresult, it was found to be 30%.

Production Example 7 Preparation of Substrate for Coating with CurableResin Composition

A surface subjected to an easy adhesion treatment of a single-sided easyadhesive polyethylene terephthalate (PET) film A4100 (film thickness:188 μm, produced by Toyobo Co., Ltd.) was coated with thezirconia-containing composition for hard coat layer prepared inProduction Example 6 by using a wire bar coater (#7), and the coatedlayer was dried in an oven at 80° C. for one minute to form a coatedfilm. Then, in the air, the film was irradiated with an ultraviolet rayby using a high pressure mercury lamp with a light irradiation conditionof 0.9 mJ/cm² to prepare a substrate for coating with curable resincomposition. The film thickness of the hard coat layer on the substratewas measured by using a stylus surface profiler and found to be 3 μm.

Hereafter, synthesis examples of the ethylenically unsaturatedgroup-containing fluoropolymers of the present invention will beexplained in Examples 1 to 7 and Comparative Examples 1 to 3.

Example 1 Synthesis of Ethylenically Unsaturated Group-containingFluoropolymer (A-1)

To a 1 L-volume separable flask equipped with an electromagneticstirrer, glass cooling pipe and thermometer, 50.0 g of the hydroxylgroup-containing fluoropolymer 1 obtained in Production Example 1, 0.01g of 2,6-di-t-butylmethylphenol as a polymerization inhibitor and 370 gof MIBK were charged and stirred at 20° C. until the hydroxylgroup-containing fluoropolymer 1 was dissolved in MIBK so that thesolution should become transparent and uniform.

Then, to this system, 15.1 g of 2-methacryloyloxyethyl isocyanate wasadded, and the mixture was stirred until it became a uniform solution.Then, 0.1 g of dibutyltin dilaurate was added to the solution toinitiate the reaction, and the mixture was continuously stirred for 5hours while the temperature of the system was maintained at 55 to 65° C.to obtain a solution of ethylenically unsaturated group-containingfluoropolymer (A-1) in MIBK. In an amount of 2 g of this solution wasweighed on an aluminum plate, dried on a hot plate at 150° C. for 5minutes and weighed to measure the solid content. As a result, it wasfound to be 15.2%. The used compounds, solvent and solid content areshown in Table 3. TABLE 3 Examples and Ex- Ex- Comparative ComparativeComparative Comparative Examples ample 1 ample 2 Example 3 Example 4Example 5 Example 6 Example 7 Example 1 Example 2 Example 3Ethylenically unsaturated A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9 A-10group-containing fluoropolymer Hydroxyl group-containing 50.0 50.0 50.050.0 50.0 50.0 fluoropolymer 1 (g) Hydroxyl group-containing 50.0fluoropolymer 2 (g) Hydroxyl group-containing 50.0 fluoropolymer 3 (g)Hydroxyl group-containing 50.0 fluoropolymer 4 (g) Hydroxylgroup-containing 50.0 fluoropolymer 5 (g) 2-Methacryloyloxyethyl 15.116.4 20.6 3.5 9.5 9.5 10.5 6.9 13.7 27.4 isocyanate (g)2,6-Di-t-butylmethyl- 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01phenol (g) Dibutyltin dilaurate (g) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.10.1 Methyl isobutyl ketone 370 377 400 304 338 338 343 323 362 439 (g)Charged amount of 2- 1.1 1.2 1.5 1.2 1.2 1.2 1.2 0.5 1.0 2.0methacryloyloxyethyl isocyanate based on hydroxyl group content ofhydroxyl group-containing fluoropolymer (molar ratio) Solidconcentration (% by 15.2 15.1 15.2 15.3 15.1 15.1 15.2 15.2 15.2 15.2weight)

Examples 2 to 7 Synthesis of Ethylenically Unsaturated Group-containingFluoropolymers (A-2 to A-7)

Solutions of ethylenically unsaturated group-containing fluoropolymers(A-2 to A-7) in MIBK were obtained in the same manner as in Example 1except that the type of hydroxyl group-containing fluoropolymer, amountsof 2-methacryloyloxyethyl isocyanate and MIBK and molar ratio ofisocyanate group to hydroxyl group used in Example 1 were changed asshown in Table 3.

Comparative Examples 1 to 3 Synthesis of Ethylenically UnsaturatedGroup-containing Fluoropolymers (A-8 to A-10)

Ethylenically unsaturated group-containing fluoropolymers (A-8 to A-10)were obtained in the same manner as in Example 1 except that the amountsof 2-methacryloyloxyethyl isocyanate and MIBK and molar ratio ofisocyanate group to hydroxyl group used in Example 1 were changed asshown in Table 3.

The ethylenically unsaturated group-containing fluoropolymers (A-8 andA-9) do not fall within the scope of the present invention because themolar ratio of isocyanate group to hydroxyl group at the time of thesynthesis is less than 1.1. Further, the ethylenically unsaturatedgroup-containing fluoropolymer (A-10) does not fall within the scope ofthe present invention because the molar ratio of isocyanate group tohydroxyl group at the time of the synthesis exceeds 1.9.

Hereafter, preparation examples of the curable resin composition of thepresent invention will be explained as Examples 8 to 16 and ComparativeExamples 4 to 6.

Example 8

As shown in Table 4, 68 g of the ethylenically unsaturatedgroup-containing fluoropolymer (A-1) synthesized in Example 1, 30 g ofneopentyl glycol diacrylate (trade name: NK Ester A-NPG, produced byShin-Nakamura Chemical Co., Ltd.) as the polyfunctional (meth)acrylatecompound containing at least two (meth)acryloyl groups (hereinafterreferred to as the “polyfunctional (meth)acrylate compound”), 2 g of2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (trade name:IRGACURE 907, produced by Ciba Specialty Chemicals) as aphotopolymerization initiator, 960 g of MIBK and 1440 g of tert-butylalcohol were charged in a separable glass flask equipped with a stirrerand stirred at 23° C. for one hour to obtain a uniform curable resincomposition (B-1). Further, the solid content was measured in the samemanner as in Example 1. TABLE 4 Example and Comparative Example ExampleExample Example Example Examples Example 8 Example 9 10 11 12 13 14Curable resin composition B-1 B-2 B-3 B-4 B-5 B-6 B-7 Ethylenicallyunsaturated group-containing fluoropolymer (g) A-1 68 A-2 68 68 18 A-368 A-4 73 A-5 68 A-6 A-7 A-8 A-9 A-10 Polyfunctional (meth)acrylate (g)Neopentyl glycol diacrylate 30 30 30 30 dipentaerythritol pentaacrylate30 25 Fluorine-containing (meth) acrylate (g) Bifunctional fluorine 3050 acrylate Photopolymerization initiator (g) IRGACURE 907 2 2 2 2 2 2 2Solvent (g) Methyl isobutyl ketone 960 960 960 960 960 960 960tert-Butyl alcohol 1,440 1,440 1,440 1,440 1,440 1,440 1,440 Solidconcentration (% 4 4 4 4 4 4 4 by weight) Characteristics of curedproduct Refractive index 1.44 1.44 1.44 1.40 1.40 1.42 1.43Antiscratching property ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Antiscratching property ο ⊚ ο ⊚ ⊚⊚ ⊚ after storage in humid and hot environment Antiscratching property ο⊚ ο ⊚ ⊚ ⊚ ⊚ after immersion in alkaline aqueous solution Coatingproperty ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Example and Comparative Example ExampleComparative Comparative Comparative Examples 15 16 example 4 example 5example 6 Curable resin composition B-8 B-9 C-1 C-2 C-2 Ethylenicallyunsaturated group-containing fluoropolymer (g) A-1 A-2 A-3 A-4 A-5 A-668 A-7 68 A-8 68 A-9 68 A-10 68 Polyfunctional (meth)acrylate (g)Neopentyl glycol diacrylate 30 30 30 30 30 dipentaerythritolpentaacrylate Fluorine-containing (meth) acrylate (g) Bifunctionalfluorine acrylate Photopolymerization initiator (g) IRGACURE 907 2 2 2 22 Solvent (g) Methyl isobutyl ketone 960 960 960 960 960 tert-Butylalcohol 1,440 1,440 1,440 1,440 1,440 Solid concentration (% 4 4 4 4 4by weight) Characteristics of cured product Refractive index 1.43 1.431.43 1.44 1.45 Antiscratching property ο ⊚ ο ⊚ ο Antiscratching propertyο ⊚ x Δ Δ after storage in humid and hot environment Antiscratchingproperty ο ⊚ x x x after immersion in alkaline aqueous solution Coatingproperty ⊚ ο ⊚ ⊚ ο

Example 9

A curable resin composition (B-2) was obtained in the same manner as inExample 8 except that the ethylenically unsaturated group-containingfluoropolymer (A-2) synthesized in Example 2 was used instead of theethylenically unsaturated group-containing fluoropolymer (A-1) as shownin Table 4.

Example 10

A curable resin composition (B-3) was obtained in the same manner as inExample 8 except that the ethylenically unsaturated group-containingfluoropolymer (A-3) synthesized in Example 3 was used instead of theethylenically unsaturated group-containing fluoropolymer (A-1) as shownin Table 4.

Example 11

A curable resin composition (B-4) was obtained in the same manner as inExample 9 except that a bifunctional fluorine-containing acrylaterepresented by the following formula (11) as the fluorine-containing(meth)acrylate compound containing at least one (meth)acryloyl group(hereinafter referred to as the “fluorine-containing (meth)acrylatecompound”) was used instead of the polyfunctional (meth)acrylatecompound as shown in Table 4.

Example 12

A curable resin composition (B-5) was obtained in the same manner as inExample 11 except that amounts of the ethylenically unsaturatedgroup-containing fluoropolymer (A-2) and the bifunctionalfluorine-containing acrylate were changed to 18 g and 50 g,respectively, and 30 g of dipentaerythritol pentaacrylate (SR399E,produced by Nippon Kayaku Co., Ltd.) was further used as apolyfunctional (meth)acrylate compound as shown in Table 4.

Example 13

A curable resin composition (B-6) was obtained in the same manner as inExample 8 except that 73 g of the ethylenically unsaturatedgroup-containing fluoropolymer (A-4) synthesized in Example 4 was usedinstead of the ethylenically unsaturated group-containing fluoropolymer(A-1) and 25 g of dipentaerythritol pentaacrylate was used as apolyfunctional (meth)acrylate compound as shown in Table 4.

Example 14

A curable resin composition (B-7) was obtained in the same manner as inExample 8 except that the ethylenically unsaturated group-containingfluoropolymer (A-5) synthesized in Example 5 was used instead of theethylenically unsaturated group-containing fluoropolymer (A-1) as shownin Table 4.

Example 15

A curable resin composition (B-8) was obtained in the same manner as inExample 8 except that the ethylenically unsaturated group-containingfluoropolymer (A-6) synthesized in Example 6 was used instead of theethylenically unsaturated group-containing fluoropolymer (A-1) as shownin Table 4.

Example 16

A curable resin composition (B-9) was obtained in the same manner as inExample 8 except that the ethylenically unsaturated group-containingfluoropolymer (A-7) synthesized in Example 7 was used instead of theethylenically unsaturated group-containing fluoropolymer (A-1) as shownin Table 4.

Comparative Example 4

A curable resin composition (C-1) was obtained in the same manner as inExample 8 except that the ethylenically unsaturated group-containingfluoropolymer (A-8) synthesized in Comparative Example 1 was usedinstead of the ethylenically unsaturated group-containing fluoropolymer(A-1) as shown in Table 4.

Comparative Example 5

A curable resin composition (C-2) was obtained in the same manner as inExample 8 except that the ethylenically unsaturated group-containingfluoropolymer (A-9) synthesized in Comparative Example 2 was usedinstead of the ethylenically unsaturated group-containing fluoropolymer(A-1) as shown in Table 4.

Comparative Example 6

A curable resin composition (C-3) was obtained in the same manner as inExample 8 except that the ethylenically unsaturated group-containingfluoropolymer (A-10) synthesized in Comparative Example 2 was usedinstead of the ethylenically unsaturated group-containing fluoropolymer(A-1) as shown in Table 4.

Test Example

Refractive index, antiscratching property and coating property of curedproducts obtained by curing the curable resin compositions of Examples 8to 16 and Comparative Examples 4 to 6 were determined by the followingmeasurement methods.

(1) Refractive Index

Each curable resin composition was applied on a silicon wafer by using aspin coater to obtain a thickness of about 0.1 μm after drying and thencured by irradiation with an ultraviolet ray under a light irradiationcondition of 0.5 mJ/cm² using a high pressure mercury lamp undernitrogen. The refractive index (^(n)D₂₅) of the obtained cured productwas measured at a wavelength of 539 nm at 25° C. by using anellipsometer. The results are shown in Table 4.

(2) Antiscratching Property

Each curable resin composition was applied on the substrate for coatingwith curable resin composition prepared in Production Example 7 by usinga wire bar coater (#3) and dried in an oven at 80° C. for one minute toform a coated film. Then, the coated film was irradiated with anultraviolet ray under a light irradiation condition of 0.5 mJ/cm² byusing a high pressure mercury lamp under nitrogen to prepare anevaluation sample. The film thickness of this cured product layer wasestimated by measuring reflectance and found to be about 100 nm.

The surface of the prepared evaluation sample was manually rubbed 200times in a reciprocal manner with cellulose non-woven fabric (tradename: BEMCOT, produced by Asahi Kasei Corporation) impregnated withethanol, and antiscratching property of the surface of the evaluationsample was evaluated by visual inspection according to the followingcriteria. The results are shown in Table 4.

-   ⊚: No scratch is observed on the surface of the evaluation sample.-   ◯: Fine scratches are present on the surface of the evaluation    sample.-   Δ: Scratches are present on the surface of the evaluation sample.-   X: Delamination of the coated film is observed.    (3) Antiscratching Property after Storage in Humid and Hot    Environment

The aforementioned evaluation sample was left standing under theconditions of 80° C. and 95% RH for one week, and then the surfacethereof was manually rubbed 200 times in a reciprocal manner withcellulose non-woven fabric (trade name: BEMCOT, produced by Asahi KaseiCorporation) impregnated with ethanol, and durability of the surface ofthe evaluation sample was evaluated by visual inspection according tothe following criteria. The results are shown in Table 4.

-   ⊚: No scratch is observed on the surface of the evaluation sample.-   ◯: Fine scratches are present on the surface of the evaluation    sample.-   Δ: Scratches are present on the surface of the evaluation sample.-   X: Delamination of the coated film is observed.    (4) Antiscratching Property after Immersion in Alkaline Aqueous    Solution

The aforementioned evaluation sample was immersed in a 2 N sodiumhydroxide aqueous solution at 25° C. for 2 minutes, washed withdistilled water and air-dried. Then, the surface thereof was manuallyrubbed 200 times in a reciprocal manner with cellulose non-woven fabric(trade name: BEMCOT, produced by Asahi Kasei Corporation) impregnatedwith ethanol, and antiscratching property after immersion in an alkalineaqueous solution of the surface of the evaluation sample was evaluatedby visual inspection according to the following criteria. The resultsare shown in Table 4.

-   ⊚: No scratch is observed on the surface of the evaluation sample.-   ◯: Fine scratches are present on the surface of the evaluation    sample.-   Δ: Scratches are present on the surface of the evaluation sample.-   X: Delamination of the coated film is observed.    (5) Coating Property

Each curable resin composition was applied on the substrate for coatingwith curable resin composition prepared in Production Example 7 by usinga wire bar coater (#3) and dried in an oven at 80° C. for one minute toform a coated film. Subsequently, the coated film was irradiated with anultraviolet ray by using a high pressure mercury lamp under a lightirradiation condition of 0.5 mJ/cm² under nitrogen to prepare anevaluation sample. The surface property of the obtained coated film wasevaluated by visual inspection according to the following four-levelcriteria (⊚, ◯, Δ, X). The results are shown in Table 4.

-   ⊚: A uniform coated film is obtained with no defect over the whole    coated film.-   ◯: A substantially uniform coated film is obtained with defects in a    part of coated film.-   Δ: Unevenness of coated film is observed with defects in a part of    coated film.-   X: Defects are observed over the whole coated film surface.    Industrial Applicability

With the ethylenically unsaturated group-containing fluoropolymer of thepresent invention, as well as the curable resin composition and theantireflection film using the same, superior antiscratching property,coating property and durability can be obtained.

1. An ethylenically unsaturated group-containing fluoropolymer, which isobtained by reacting a compound containing one isocyanate group and atleast one ethylenically unsaturated group, and a hydroxylgroup-containing fluoropolymer at an isocyanate group/hydroxyl groupmolar ratio of 1.1 to 1.9, contains 20 to 70% by mole of the followingstructural unit (a), 10 to 70% by mole of the following structural unit(b), 5 to 70% by mole of the following structural unit (c) and 0.1 to10% by mole of the following structural unit (d) and has a numberaverage molecular weight of 5,000 to 500,000 in terms of polystyrene asmeasured by gel permeation chromatography: (a) a structural unitrepresented by general formula (1); (b) a structural unit represented bygeneral formula (2); (c) a structural unit represented by generalformula (3); (d) a structural unit derived from an azo group-containingpolysiloxane compound and represented by the following general formula(4);

wherein, in the general formula (1), R¹ represents a fluorine atom,fluoroalkyl group or group represented as—OR² (R² represents an alkylgroup or fluoroalkyl group);

wherein, in the general formula (2), R³ represents a hydrogen atom ormethyl group, R⁴ represents an alkyl group, group represented as—(CH₂)_(x)—OR⁵ or —OCOR⁵ (R⁵ represents an alkyl group or glycidylgroup, and x represents a number of 0 or 1), carboxyl group oralkoxycarbonyl group;

wherein, in the general formula (3), R⁶ represents a hydrogen atom ormethyl group, R⁷ represents a hydrogen atom or hydroxyalkyl group, and vrepresents a number of 0 or 1;

wherein, in the general formula (4), R⁸ and R⁹ may be identical ordifferent and represent a hydrogen atom, alkyl group, halogenated alkylgroup or aryl group.
 2. (Deleted)
 3. (Deleted)
 4. The ethylenicallyunsaturated group-containing fluoropolymer according to claim 1, whichcontains the structural unit (d) as a part of the following structuralunit (e): (e) a structural unit represented by the following generalformula (5):

wherein, in the general formula (5), R¹⁰ to R¹³ represent a hydrogenatom, alkyl group or cyano group, R¹⁴ to R¹⁷ represent a hydrogen atomor alkyl group, p and q represent a number of 1 to 6, s and t representa number of 0 to 6, and y represents a number of 1 to
 200. 5. Theethylenically unsaturated group-containing fluoropolymer according toclaim 1, which further contains 0.1 to 5% by mole of the followingstructural unit (f): (f) a structural unit represented by the followinggeneral formula (6):

wherein, in the general formula (6), R¹⁸ represents a group havingemulsifying action.
 6. The ethylenically unsaturated group-containingfluoropolymer according to claim 1, wherein the compound containing oneisocyanate group and at least one ethylenically unsaturated group is2-(meth)acryloyloxyethyl isocyanate.
 7. A curable resin compositioncomprising the ethylenically unsaturated group-containing fluoropolymeraccording to claim 1, and a polyfunctional (meth)acrylate compoundcontaining at least two (meth)acryloyl groups and/or afluorine-containing (meth)acrylate compound containing at least one(meth)acryloyl group.
 8. An antireflection film containing a lowrefractive index layer comprising a cured product obtained by curing thecurable resin composition according to claim 7.